Astronomical spectroscopy for research, industry, education and leisure

Alpy Description

***** HOT PRODUCT *****
Sky & Telescope, January 2014

ALPY is a modular product line for spectroscopy.



ALPY allows progressive investment with separate spectroscope, guiding and calibration modules. It is multi-purpose (on a bench or with a telescope; slit, slitless or with an optical fiber connector; visual use, with CCD camera or digital SLR…) and very easy to use with minimum adjustements to make. ALPY is an efficient system with, for the Alpy 600, a spectral domain from near-UV to near-IR with a resolution around 10A.

The core element of the ALPY product line is the Alpy 600 spectroscope. With a 600gr/mm grism (grating + prism), Alpy 600 offers compactness, low resolution (resolving power R~600) and a dispersion compatible with the current CCD cameras used in astronomy. The spectroscope is F/4.
The ALPY product line has been designed around standard mechanical threads (M42x075, SM1, SM05) to facilitate integration with your existing instrumentation.
Collimator focal is 19.5mm and objective lens focal is 20mm; so the Alpy 600 magnification factor is close to 1x.
The ALPY product line also includes a separate guiding module (mirror slit 23µm) and a calibration module with neon/argon and tungsten lamps. That makes a complete solution for astronomical spectroscopy, with each module being independent, making ALPY unique and revolutionary.

Alpy 600 + guiding module on FSQ80 (C. Buil)

Progressive investment (“à la carte”)
You have the choice of which module to purchase based on your budget and need. You can then upgrade your equipment over time through further investment. Discover slit based spectroscopy with the Alpy 600 base module which will bring you lot of possible observations on a workbench or at your telescope. Complete your investment with a guiding module, allowing longer exposures with your CCD camera to reach fainter targets. Then add a calibration module to get easier and more accurate wavelength calibration (neon/argon) and flats (tungsten).

Beyond the modularity between the Alpy 600 spectroscope and guiding and calibration modules, the spectroscope itself is versatile and multi-purpose.
It is able to interface with most CCD cameras with a standard M42x0.75mm thread. A C-mount adapter is available as well as a barlow lens element specially designed for Digital SLRs, extending the backfocus and enlarging the spectrum.
The removable standard slit includes multiple positions (25µm hole; 25µm, 50µm, 100µm or 300µm slits; 5µm tolerance) with a clear position (3mm hole) for a slitless mode.
A “fiber connector” mounting is also available so Alpy 600 is compatible with our optical fiber eShel solution.
Last but not least, Alpy 600 is also a visual spectroscope (with or without slit), to be used as a 1.25inch eyepiece:
-extended objects with a slit (25µm typycally, eventually 50µm): Moon, planets, bright nebulaes (like M42, Orion nebula, seen visually with a 85mm refractor);
-bright stars with the slit, by defocusing the star image on the slit to get a vertically expanded spectrum and make the absorption lines more visible;
-some broad emission line spectra objects with a very large slit (3mm hole): blink nebula, Wolf-Rayet stars…

Alpy 600: CCD camera & Visual modes

Easy to use
The low weight (<200gr, without camera), compactness and modularity makes Alpy 600 very easy to use. The guiding module is also very straight forward to use. There are very few adjustments to make.

Alpy 600 slit


The ALPY product line benefits from our experience and expertise in the area of astronomical spectroscopy. For example, the Alpy 600 optics have been specially designed for this spectroscope, giving an excellent quality spectrum through all the visible domain from near-UV (Balmer serie, astonishing H&K lines) to near-IR (calcium triplet).

Table: spectral domain covered Vs sensor width (in mm)
with or without the Alpy barlow lens element

Here are some links to preliminary results from early production prototypes:


Alpy 600: Orion nebulae (C11, 30s exposure). Guiding img: Atik 314L+; spectrum: Atik 460EX. C. Buil

Spectrum of 53 Leo (Alpy 600, C8, Atik 314L+)F. Cochard – N. Durand